body {
    margin:0px;
    width:300px;
} 
button {
    font-family:'Segoe UI', Tahoma, Geneva, Verdana, sans-serifs;
    font-size:11px;
    border:none;
    margin:1px;
}
.clicked {
    background-color:blue;
    color:white;
}
.unclicked {
    background-color:lightgray;
    color:black;
}
